duplicate a mesh on the top (many times)
In the Properties menu at the right, go to the Modifiers section:

Select Add Modifier and select Array:

Change the Relative Offset value on the top (the X axis value) to 0:

Change the Relative Offset value on the bottom (Z axis) to 1:

Change the Count value to however many duplicates you want:


If you actually want the original object on the top like in your example, change the Relative Offset bottom value (Z axis) to -1 instead of 1.

The duplicates will not be editable as actual mesh by default. The advantage to this is that you can change all your settings as many times as you want, but if you want actual mesh duplicates click the Apply button on the Array modifier.